Cognitive therapy and brain training
Screening: Alertness
www.rehacom.com
Cognitive therapy and brain training by Hasomed GmbH
This manual contains information about using the RehaCom therapy system. Our therapy system RehaCom delivers tested methodologies and procedures to train brain performance . RehaCom helps patients after stroke or brain trauma with the improvement on such important abilities like memory, attention, concentration, planning, etc. Since 1986 we develop the therapy system progressive. It is our aim to give you a tool which supports your work by technical competence and simple handling, to support you at clinic and practice.
HASOMED GmbH Paul-Ecke-Str. 1 D-39114 Magdeburg Tel: +49-391-6107650 www.rehacom.com
Inhalt
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Inhaltsverzeichnis Teil I Applications
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Teil II Target group
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Teil III Structure
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Teil IV Implementation and Duration
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Teil V Data analysis
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Teil VI Bibliography
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Index
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Alertness
Applications Basic information on the screening you will find in the RehaCom manual, Chapter "Screening and Diagnostics". Alertness describes the general alertness, which makes it possible to react fast and appropriate to a certain requirement. Alertness is the basis for any attention performance and therefore the precondition for adequate action. A distinction is made between the "tonic arousal", the general state of being awake, and the "phasic arousal" which describes the increased responsiveness in anticipation of an expected event. Today, the following, very different processes are summarized in the term "Alertness": general alertness ("tonic arousal") maintenance of responsiveness over a longer period of time ("intrinsic alertness") short- term focusing of attention on an expected event ("phasic arousal"). It is checked by means of a simple visual or auditory reaction task (without intrinsic control of the activation level, tonic course of the activation level) or with a warning stimulus (phasic activation).
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Applications
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Figure 1: Alertness test
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Target group Attention disorders may occur in almost all neurological diseases, which affect the central nervous system. Depending on whether these diseases lead to rather circumscribed and localized brain damages (such as a stroke) or to rather diffused impairments (such as traumatic brain injury or degenerative diseases), the malfunction in the attention area can be rather specific or global. Cerebrovascular Diseases After lesions in the brain stem portion of the formatio reticularis (Mesulam 1985) and after strokes, especially in the area of the median brain artery (A. cerebri media) of the right brain hemisphere, disorders of attention activation as well as the vigilance and the long-term maintenance of attention can occur (Posner et al. 1987). While the reticular system of the brain stem portion is the "noradrenergic source" of attention activation(Stuss u. Benson 1984), the frontothalamic "Gating-System" controls the selective and directed allocation of this attention activation. Lesions of this system lead to a limited selectivity for external stimuli and to increased distractibility, i.e. to disorders of the attention focus. Lesions especially of frontal parts of the left hemisphere, also cause impairments of attention selectivity, especially in situations, in which fast decisions between relevant and irrelevant aspects of a task have to be made (Dee u. van Allen 1973, Sturm u. Bussing 1986). Disorders of spatial attention can be selectively affected by localized brain damages. Damages of the posterior parietal lobe seem to lead especially to disorders of disengaging the attention off a stimulus, when the attention must be moved towards a target stimulus in the room half on the opposite side of the lesion (Posner et al. 1984). Here, a cause for a unilateral neglect after a parietal lesion is seen (see guidline "Rehabilitation of disorders of spatial cognition"). Disorders of divided attention seem to occur particularly often after bilateral frontal vascular damages (Rousseaux et al. 1996). Traumatic Brain Injury (TBI) Along with memory disorders, attention impairments are the most common neuropsychological deficits after a TBI. The most consistent result after TBI is a general, non-specific slowdown of the information processing. The cause of this malfunction after TBI remains largely unclear. As a pathological correlate of the damage due to the mainly rotational acceleration of the brain, "diffuse axonal damages" are discussed or a hypometabolism in prefrontal and cingulate brain areas (Fontaine et al. 1999). Multiple Scleroses
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Alertness
Cognitive slowing and increased variability with an often preserved performance quality at the beginning of the disease is a widespread deficit in patients with multiple sclerosis, so that tests with reaction time measurement are of special significance in this disease. It is obvious, that this retardation relatively independent of the individual sub-functions of the attentional performance. As neuronal basis, a diffusely localized axonal damage and demyelination is assumed, whose counterpart a generally increased degree of brain atrophy could be proved (e. g. Lazeron et al. 2006). Neurodegenerative Diseases Already at the early stage of Alzheimer- dementia (AD), attention deficits are often seen. They often seem to occur after memory disorders, but before impairments of language and spatial performances (Perry et al. 2000). Other results indicate a relative maintenance of the cognitive control of attention activation and visuo-spatial attention, but also early disorders of the selective attention. In the course of the disease, also disorders of the inhibitory control increase. In Lewy body dementia, fluctuating attention performances and deficits in the visuospatial attention are a central diagnostic criterion. Recent studies (Calderon et al. 2005) reported that clients showed significant worse results in almost all attention functions (sustained attention, selective attention, divided attention) compared to AD-patients. Patients with Parkinson's disease or Huntington's chorea generally show no deficits in phasic alertness and vigilance tasks, whereas patients with progressive supranuclear paralysis (Steele-Richardson-Olszewski-Syndrome) suffer from such disorders. Disorders of the divided attention seem to be a general problem in dementia diseases in later stages of diseases. Depression and Attention Disorders Even in case of depression, memory and attention disorders are to the fore of the cognitive functional impairments. Primarily, conscious cognitive controlled functions are affected. Especially the performance during tasks for the attention distribution has been identified as a prognostic parameter (Majer et al. 2004). Only in very severe depressions, disorders of automatic processing can be present (Hartlage et al. 1993). In comparison to e.g. patients after traumatic brain injury (TBI) depressed patients often estimate their performances worse than they actually are in the psychometric examination. Farrin et al. (2003) could show that this negative selfassessment, e.g during task for sustained attention, can lead to "disaster reactions" after mistakes with an enlarged reaction times immediately afterwards. TBI -patients did not show such reactions. Source: Leitlinien fĂźr Diagnostik und Therapie in der Neurologie; 4. revised edition, ISBN 978-3-13-132414-6; Georg Thieme Verlag Stuttgart
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Structure
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Structure The reaction time is checked under two conditions. 1.Condition An object appears on the screen which has to be fixed.
In randomized intervals the object changes.
The task is to react as fast as possible to the changed object by pressing a button. The maintaining of the responsiveness is measured here over a longer period of time, the so called intrinsic alertness.
2. Condition An object appears on the screen which has to be fixed.
Before the object changes in randomized intervals, an acoustic cue stimulus (warning sound) is given.
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Alertness
The temporal alignment of the attention focus is measured here, the so called phasic arousal.
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Implementation and Duration Implementation The test starts with an exercise, in which advices appear, if incorrect (to early, no) reactions were made. The exercise is not completed until 2 consecutively correct reactions were made in each run. Following the exercise, the test is also performed in two parts, in a simple ABdesign: 1. Run without warning sound, 2. Run with warning sound. The instructions are: For 1.: You look at this object.
If now this object
appears on the screen, press the OK button as fast as possible. For 2.: You look as this object.
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Implementation and Duration
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You hear a sound. If this object appears afterwards,
press the OK button. Do not press directly after the sound but only when this object
appears. In each run, two sample stimuli are given first, which are excluded in the analysis. If the reaction was incorrect, up to five additional stimuli appear. Each run consists of a maximum of 27 stimuli. Duration maximum of 6 min (without practice)
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Data analysis Basic information on the data analysis of screening results you will find in the RehaCom manual, chapter "Results screening". In the screening Alertness, two Z-values are calculated. Z-value 1: tonic alertness Median of all reactions without warning sound Z-value 2: phasic alertness Characteristic value for the difference of the reaction times between the single parts of the screening without and with warning sound. Details
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Alertness
Detailed information on the course of the screening can be displayed via the button "Details". On the right side is a list of all conducted screenings for Alertness and their end times. Results marked with an asterisk (*) indicate that the particular screening was canceled. In this case, the evaluation is incomplete - e.g. no Z-values are indicated. The detailed analysis allows the presentation of a maximum of three results at the same time. The first and the last fully completed screening is preselected. One can change the selection by clicking the particular checkbox. The display in the diagrams changes accordingly. The background color of each result row corresponds to the line color in the diagram and the tab color in the summary. The following data are available for evaluation: The median reaction time measures the general processing speed and thus provides indications on the slowing down caused by the brain damage. The variability of the reaction time is a measure of the stability of the performance level. Higher standard deviations indicate low stability. A trend in the response times in the direction of longer times indicates a (fast) fatigue and thus the decrease of tonic arousal.
Abb.1: Verlauf Reaktionszeiten
In the diagram "Reaction times" (fig. 1) all single reaction times are presented. If the subject didn't react to a stimulus or reacted before the stimulus presentation, no marker is drawn. Thus, a dotted line is shown. The stimuli 21-25 are only available if the subject reacted incorrectly during the regular stimuli (1-20). To accurately display a reaction time one can click on the square marker. The maximum and minimum
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Data analysis
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reaction time of a screening are displayed automatically.
Abb.2: Auswertung Reaktionszeiten
On the tab "Summary", information on how to determine the Z-values as well as the parameters (mean value, median, standard deviation etc.) are indicated for each run. Fig. 2 shows that the median of the reactions times of the runs without warning sounds is used as the first Z-value. Behind it, the used comparison standard with the resulting Z-value is presented. For the comparison standards a reliability estimation using split-half method has been performed. Cronbach's alpha for the reaction times without sound is 0.99. With sound this value is 0.97. If the reaction time without warning sound is slowed down compared to the healthy age group, this may be an indication for rapid fatigability. A significant increase of the reaction times indicates a reduced intrinsic alertness. The standard degression (variability) of the reaction time can provide information on the constancy of the performance. The difference of the reaction times without and with warning sound is the measure for the phasic alertness. The keyword of the phasic alertness is calculated according to the following formula: (MedRZo - MedRZm ) / MedRZges MedRZo
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- Median reaction times without warning stimulus
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Alertness
MedRZm
- Median reaction times with warning stimulus
MedRZges
- Median of all reaction time
An increased number of omissions may be an indication for increased reaction latency and should be related to the results of the Go/ Nogo Screenings. Anticipation: If the subject pressed the button before the stimulus is presented or if the reaction time is less than 100 ms. Outlier: Each reaction time, which lies over the mean reaction time plus the 2.35-times standard deviation.
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Bibliography Thöne-Otto, A., George, S., Hildebrandt, H., Reuther, P., Schoof-Tams. K., Sturm, W., & Wallesch, C.-W. (2010). Leitlinie zur Diagnostik und Therapie von Gedächtnisstörungen. Zeitschrift für Neuropsychologie, 21, 271-281. Griffin, I.C. & Nobre, A.C. (2005). Temporal Orienting of Attention. In L. Itti, G. rees & J.K. Tsotsos (Hrsg.), Neurobiology of Attention. Burlington, MA: Elsevier. Sturm, W. (2002). Diagnostik von Aufmerksamkeitsstörungen in der Neurologie. Aktuelle Neurologie, 29, 25-29. Sturm W., de Simone A., Krause B.J., Specht K., Hesselmann V., Radermacher I., Herzog H., Tellmann L., Müller-Gärtner H.W. & Willmes K. (1999). Functional anatomy of intrinsic alertness: evidence for a fronto-parietal-thalamic-brainstem network in the right hemisphere. Neuropsychologia, 37, 797-805. Coull, J.T. & Nobre, A.C. (1998), Where and when to pay attention: The neural system for directing attention to spatial locations and to time intervals revealed by both PET and fMRI. Journal of Neuroscience, 18, 7426-7435. Posner, M.I. & Petersen, S.E. (1990). The attention system of the human brain. Annual Review of Neuroscience, 13, 25-42. Posner, M.I., Walker, J.A., Friedrich, F.A. & Rafel, R.D. (1984). Effects of parietal injury on covert orienting of attention. Journal of Neuroscience, 4, 1863-1874. van Zomeren, A.H. (1981). Reaction Time and Attention after Closed Head lnjury. Rijksuniversiteit Groningen: Dissertation. Posner, M.l. (1978). Chronometric Explorations of Mind. Hillsdale, NJ: Erlbaum.
© 2014 HASOMED GmbH
Bibliography
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Posner, M.I. & Boies, S.J. (1971). Components of attention. Psychological Review, 78, 391-408. Leitlinien fur Diagnostik und Therapie in der Neurologie; 4. überarbeitete Auflage, ISBN 978-3-13-132414-6; Georg Thieme Verlag Stuttgart
© 2014 HASOMED GmbH
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Alertness
Index
-Ggeneral processing speed
-A-
-I-
activation level 1 advice 5 alertness 1 alzheimer- dementia anticipation 6 arousal 4 attention 1, 2 attention focus 4 auditory 1
instructions 5 intervals 4
-K-
2
keyword
lesions
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cerebrovascular diseases conditions 4
marker 6 median 6 multiple scleroses 2
data analysis 6 depression and attention disorders details 6 diagram 6 duration 5
-Ffatigability 6 focusing 1
2
-N-
-D-
errors 6 evaluation 6 exercise 5
2
-M-
-C-
-E-
6
-L-
-Bbibliography
6
neurodegenerative diseases
2
-O2 outlier
6
-Pperformance 1, 6 performance level 6 phasic 4 phasic alertness 6 phasic arousal 1 presentation 6
-Rreaction task 1 reaction time 6 responsiveness 1, 4
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Index results
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-Sstandard structure summary
6 4 6
-Ttarget group 2 task 6 tonic alertness 6 tonic arousal 1, 6 traumatic brain injury
-Vvariability 6 vigilance 2 visual 1
-Wwarning sound
4, 5, 6
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